Improved durability testing for field placed concrete and emerging cement systems

混凝土结构越来越多地按照基于性能的规范来建造。这导致了该行业的创新，因为生产商能够以新的方式利用传统材料或非传统材料，因为它们不再受到规定要求的限制。拟议的计划将包括对新兴水泥系统的耐久性调查，如石灰石水泥、新开发的混合水泥和碱激发系统。性能规范通常包括对现场生产的样品进行的标准化测试。不符合性能标准可以追溯到不适当的混合料交付，但也可能是由于施工实践不佳。由于后者没有得到很好的研究，因此计划检查目前用于检测(鉴定)养护不良或固结混凝土的耐久性试验的敏感性。 随着大型项目建设的快速推进，及时确定合规性是必要的。随着混凝土性能的发展，对现场实际浇筑的混凝土进行检测是很重要的，因此发展原位无损检测是必要的。本程序将研究吸收、表面电阻率和嵌入式电传感器等方法在此类情况下的使用。由于现场条件的变化，如温度和相对湿度可能会影响测试结果，因此也将调查这些影响。 该计划旨在通过研究材料选择和场地问题对耐久性的影响，结合实验室和现场测试，对混凝土系统采取一种新的方法。预计将就不良安置做法对耐久性的影响发表原创意见，为生产者和承包商提供有关现场问题的有用信息，以及适当的早期现场测试。这项研究的结果有可能对现场测量混凝土性能的方法产生重大影响，并增强工程师和行业的知识。

Increasingly, concrete structures are built according to performance-based specifications. This leads to innovation in the industry as producers are able to utilize traditional materials in new ways or unconventional materials since they are no longer constrained by prescriptive requirements. The proposed program will include durability investigations of emerging cement systems; such as limestone cements, newly developed blended cements, and alkali-activated systems. Performance specifications typically consist of standardized tests performed on site-produced specimens. Non-conformance to performance measures can be traced to improper mixture delivery, but could also result from poor construction practice. As the latter is not well studied, it is planned to examine the sensitivity of current durability tests for the detection (identification) of poorly cured or consolidated concrete. As construction proceeds rapidly on large scale projects, timely determination of compliance is desired. As it is important to test actual field-placed concrete as its properties develop, developments for in situ non-destructive testing are necessary. This program will examine such methods as absorption, surface resistivity, and embedded electrical sensors for their use in such instances. As changing site conditions, such as temperature and relative humidity may affect test results, these influences will be investigated as well. The program aims to take a novel approach to concrete systems through study of the impact of material selection and site issues on durability that will combine laboratory and field testing. Original contributions are anticipated regarding the influence of poor placement practices on durability providing useful information to producers and contractors regarding site issues as well as appropriate early situ testing. The results of this research have the potential to significantly influence the method in which concrete performance is measured on site and enhance the knowledge of engineers and industry.